Chloral Hydrate Solution Research Articles

A Method for the Relaxation and Immobilization of Pulmonate Snails

In studies on the biological control of schistosome-bearing snails, the inoculation of microorganisms into pulmonate snails proved to be exceedingly difficult. Methods available for relaxing mollusks were ineffective. Most of the chemical agents recommended in the past for relaxing mollusks, including chloral hydrate, cocaine, carbon dioxide, chlorotone, nembutal, and aqueous and alcoholic solutions of menthol (Berry, 1943; Hubendick, 1954; Lee, 1950; van der Schalie, 1954), were intended primarily to facilitate killing, fixing, and to provide specimens for dissection. Our snails rarely recovered after being exposed to concentrations required for adequate relaxation. It has been our experience that prolonged exposure to certain of these chemical agents, as required for adequate relaxation, disturbed the osmo-regulatory mechanism of the snail's tissues, permitting an increase of hemolymph in the foot and neck sinuses resulting in swelling of these regions. Injection into these distended regions often resulted in profuse hemorrhage. In the present study a method was developed which results in complete exposure of the anterior portion of the snail's body and in preventing its subsequent retraction until inoculation is completed. Two inherent difficulties associated with inoculating snails, (1) the intense withdrawal reaction to tactile and chemical stimuli and (2) the lack of resistance offered by their tissues to positive pressure, are successfully controlled. The technique is a two-step procedure incorporating both chemical and mechanical action. In the first step, the snail is partially narcotized to facilitate subsequent mechanical extension and immobilization. Narcotization is accomplished by immersing the snail in a 0.5 to 1.0 percent aqueous solution of urethan2 (ethyl carbamate). The concentration of urethan and the interval of exposure are dependent upon the species and size of the snail. We have found that a concentration of 0.5 percent urethan and an exposure of three to five hours were suitable for Australorbis glabratus and Helisoma anceps having a shell diameter of 10.5 to 15.5 mm. Australorbis having a shell diameter greater than 16.0 mm. were kept overnight (15-18 hrs.) in a 0.5 percent solution. In a series of experiments (Table 1) it was observed that Australorbis would recover from exposures of 48 hours at concentrations of 0.5 percent urethan. A proper degree of narcotization generally results in the protrusion of the preputium.

An improved Technique for Permanent Mounts of small Insects and Nematodes

An improved technique is described for the preparation of permanent mounts of small Arthropoda and Nematoda, using a phenol-balsam mounting medium; a method is also described for clearing live, or freshly killed, specimens in strong chloral hydrate solution. The essential feature of the mounting method is the transfer of the specimen to a slide, in a drop of phenol, to which dry, powdered balsam is added and allowed to dissolve in situ. The mount is then dried and later covered in the usual fashion.

On the structure of conidia of Cochliobolus miyabeanus.

1. The so-called “septa” that were seen in the fresh conidia of Helminthosporium oryzae (Perfect stage: Cochliobolus miyabeanus) have entirely varished, when observed soon after germination. Each component cell of the conidia rounded up into a spherical body, linked together forming a necklacelike chain. Before germination, these spherical bodies fill completely the integument of conidia, and the area of contact of two bodies gives an optical appearance of cross wall. In this respect the present fungus resembles that of Cercospora beticola and Septoria apii-graveolentis, as reported by Frandsen (1955) and MacMillan et al. (1942) respectively.2. Later, the chain of spherical bodies are in most cases severed into two fragments, generally at the central part. The bodies in a chain are tied to each other with slender connectors.3. As germination advances, the spherieal bodies, one by one from the innermost in the chain, lose their contents and become vacant, apparently sending nutrients to the germ tube.4. When conidia are cut or pressed, the spherical bodies are often separated from the chain. The disjunct single bodies, thus split out of the conidial integument, are still able to germinate.5. Lining the chitinous, brown integument of the conidium a colorless, non-chitinous membrane is oberved. This inner membrane is dissoluble in chloral hydrate solution.6. Shrivelled conidia, not only old viable ones but also those killed with alcohol, could expand in water or with expired air. The expansibility seems to be due to the nature of the inner membrane of the conidia.

Lifetime of Intermediates in Water Subjected to Electron Irradiation

Effects of ionizing radiation on water and aqueous solutions are usually interpreted on the basis of mechanisms which involve the free radicals H and OH as intermediates (1). In previous work by Allen and the author (2, 3), the steadystate pressure of gaseous products over water subjected to 1-Mv electrons was found to increase approximately as the square root of the radiation intensity. This dependence of product concentration on radiation intensity was interpreted as arising from the competition between radical-radical reactions which lead to decomposition products, and radical-product back reactions. Intermittent irradiation of pure water with an electron beam should yield information about the lifetime of intermediates just as intermittent illumination has in photochemistry (4). Hart and Matheson (5) have studied the chain lifetime in decomposition of hydrogen peroxide by mounting samples on a wheel and rotating them through a Co60 y-ray beam at various speeds. Hummel et al. (6) have studied the chain lifetimes in chloral hydrate solution and in water-saturated chloroform by means of a y-ray beam interrupted with a rotating sector. Gamma or X-ray irradiation of pure water leads to very low steady-state concentrations of the decomposition products. With irradiation of higher intensity, such as is obtainable with an electron beam from a Van de Graaff generator, the steadystate concentrations of products in pure water are high enough to be measured conveniently and effects of adventitious impurities are lessened. Intensities a thousand times as great as those used in the experiments described here are easily obtained, and the study of chemical effects produced by electron irradiation of such high intensities is an almost unexplored field. As the spurs of adjacent electron tracks tend to overlap, one would expect, in aqueous solution, higher molecular yields and lower radical yields in the direction of effects produced by heavy particles. Reported here are some experiments showing the increase in steady-state hy-

Irradiation of Chloral Hydrate Solutions

Irradiation of Chloral Hydrate Solutions

Pollen Tubes in the Style after Chloral Hydrate and Aceto-Carmine

In styles, which contain a conducting tissue, the pollen tubes can be stained with aceto-carmine and so distinguished from the conducting tissue. Pollinated styles are macerated in a saturated aqueous solution of chloral hydrate. The time of treatment is specific for each kind of style (0.5-24 hr). The stigma, with its conducting tissue, is dissected under a dissecting microscope, placed on a slide, a drop of aceto-carmine added and the preparation covered with a cover slip. By a slight pressure on the cover slip, the conducting tissue is spread out. Aceto-carmine is added from time to time during 24 hr, and the pollen tubes, especially their ends, stain a deep red. The cells of the conducting tissue are only faintly stained. In styles which have a length of only a few millimeters, the pollen tubes can be seen without dissecting the conducting tissue. The preparations can be made relatively permanent by sealing the covers with Kronig'schem Glasskitt (Hollborn und Sohne, Leipzig, Germany).

IRRADIATION OF AQUEOUS CHLORAL HYDRATE SOLUTIONS WITH Co60 GAMMA-RAYS: AVERAGE LIFETIME OF THE FREE RADICAL CHAINS

When aqueous one molar chloral hydrate solutions are irradiated with X rays or gamma-rays, hydrochloric acid is produced. The reaction appears to be a chain reaction. The average free radical chain lifetime, as determined using a rotating sector, is approximately 0.1 sec.

Cytogenetics ofLathyrus SativusLinn.

SUMMARYCytological studies of Lathyrus sativus has been made. Mitosis has been studied with pre-treatment of root tips with 0.25% aqueous chloral hydrate solution for ½ hour and with 0.002 to 0.003 Mol. aqueous Oxyquinoline solution for 2 to 3 hours at 15°-18° C. The effect of the two treatments are similar, but in case of chloral hydrate the contraction is less severe. The 14 diploid chromosome can be classified into five different types each distinguishable from the other by its size, relative position of primary and secondary constrictions. There are two chromosomes with secondary constrictions and one with a satellite corresponding to those three nucleoli observed in first meiotic telophase and in the tetrad nucleus during formation of pollen grains. Behaviour of meiotic chromosomes is normal suggesting the diploid nature of the species.*

IRRADIATION OF ONE MOLAR AQUEOUS CHLORAL HYDRATE SOLUTION WITH Co60-GAMMA-RAYS AND BETATRON X RAYS

The production of acid by irradiation of 1 M chloral hydrate solutions is proportional to the dose at a given dose rate. The specific yield is the same for Co60 γ-rays as for 23 Mev. peak energy X rays and is a linear function of the inverse of the square root of the close rate. The reaction is apparently a chain reaction.

X-Ray Dose Determinations with Chloral Hydrate

The chemical effects of x-rays on aqueous solutions of chloral hydrate (CCl3CH(OH)2) have been studied. The primary reaction is the conversion of the organic halogen to HCl and the resulting changes in electrical conductance have been used for the determination of x-ray dosage. The change in conductance is linear with x-ray dose and independent of dose-rate over a wide range. This compound has been used to determine the total output and depth-dose curves from a high intensity beryllium window x-ray tube.

The Influence of Chloral Hydrate on Serum Anaphylaxis

We found that by injecting a solution of chloral hydrate which was just sufficient in strength to produce hypnosis, 75 per cent of all serum-sensitized guinea-pigs were completely protected from a second injection of serum into the peritoneal cavity, whereas 90 per cent of controls died. We believed that with improved technic in the dosage of chloral hydrate it would be possible to protect 90 per cent of all sensitized guinea-pigs. By fully sensitized, we meant that at least three weeks' or a month's time should have elapsed before the second injection of serum into guinea-pigs which had received horse serum alone (1/100 to 1/500 c.c); at least seven or eight weeks should have elapsed before the second injection. By allowing the above interval of time to elapse; over 90 per cent of our controls died within an hour, most of them within 20 minutes.